Radiotherapy vs Catheter Ablation for Ventricular Tachycardia in Structural Heart Disease

Inclusion Criteria: 1. Structural heart disease (including ischaemic cardiomyopathy , non-ischaemic cardiomyopathy or congenital heart disease and defined as any one of 1. segmental or global decreased ventricular wall motion as defined by TTE, CT or cMRI 2. myocardial hypertrophy 3. myocardial scar (evidenced by late gadolinium enhancement on cMRI, wall thinning on cardiac CT, low voltage on electrophysiological study or abnormal intracardiac echocardiography) 2. Recurrent monomorphic VT which can include 1. at least one episode of VT treated by ICD and/or 2. sustained VT (lasting \>30s) and/or 3. inducible sustained VT on invasive electrophysiological study (EPS) or non-invasive programmed stimulation (NIPS) 3. PAINESD score of ≥9 points and/or at least moderate risk of VT recurrence or death as defined by the I-VT score. Both are validated tools used clinically to identify patient at high risk of VT recurrence and/or mortality after CA. Exclusion Criteria: 1. Age \< 18 years 2. Life expectancy \< 3 months 3. Catheter ablation deemed futile or with prohibitive risk by cardiac electrophysiologist. 4. Unwilling or unable to provide consent 5. Known cardiac channelopathies (e.g. Catecholaminergic polymorphic ventricular tachycardia (CPVT), long- or short QT syndrome, Brugada syndrome) 6. Contraindications to radiotherapy as deemed by referring physician and/or radiation oncologist 7. Pregnancy or breast feeding